For example, these slide type electronic devices include a slide type cellular phone, a slide type PDA, and the like. Generally, in a slide type electronic device, electronic components integrated in a first frame and a second frame are electrically connected by wiring such as a flexible board (Flexible Printed Circuit board: FPC) extending through a first opening portion and a second opening portion formed in opposing surfaces of the frames.
The wiring such as an FPC is designed so as to have such a length that it is not broken by application of stress even when the second frame is slid to the maximum relative to the first frame. Specifically, a margin is provided for the wiring. The margin portions come in and go out of the first opening portion and the second opening portion when the second frame is slid relative to the first frame. Therefore, in order not to inhibit the coming and going of the wiring, the first opening portion and the second opening portion have a considerably large clearance as compared to the dimension of the wiring.
Japanese laid-open patent publication No. 2005-135417 discloses a slide type cellular phone as an example of slide type electronic devices. This slide type portable terminal has a first frame and a second frame mounted on the first frame so as to be slidable relative to the first frame. Electronic components integrated in the first frame and the second frame are electrically connected by an FPC extending through a first opening portion and a second opening portion formed in opposing surfaces of the first frame and the second frame, which is not illustrated. The FPC comes in and goes out of the first opening portion and the second opening portion when the second frame is slid relative to the first frame. In order not to inhibit the coming and going of the FPC, the first opening portion and the second opening portion have a considerably large clearance as compared to the dimension of the FPC.
FIGS. 1A to 1D show a slide type cellular phone similar to one disclosed in Japanese laid-open patent publication No. 2005-135417. This slide type cellular phone has a first frame 61 and a second frame 62 mounted on the first frame 61 so as to be slidable relative to the first frame. In order to slide the second frame 62 without friction, a gap G is formed between the first frame 61 and the second frame 62.
A first circuit board 66, as a first electronic component integrated in the first frame 61, and a second circuit board 67, as a second electronic component integrated in the second frame 62, are electrically connected to each other by an FPC 70 extending through a first opening portion 61a and a second opening portion 62a formed in opposing surfaces of the first frame 61 and the second frame 62. The reference numerals 71 and 72 represent connectors.
The FPC 70 comes in and goes out of the first opening portion 61a and the second opening portion 62a when the second frame 62 is slid relative to the first frame 61. In order not to inhibit the coming and going of the FPC 70, the first opening portion 61a and the second opening portion 62a have a considerably large clearance as compared to the dimension of the FPC 70.
In the slide type electronic devices including one shown in FIGS. 1A to 1D foreign substances such as dust or moisture may enter a gap formed between a first frame and a second frame.
There have heretofore been taken no countermeasures against foreign substances such as dust or moisture entering a gap. Dust or moisture entering the gap may enter the first frame through the first opening portion, thereby causing damage to the first electronic device. Furthermore, dust or moisture entering the gap may enter the second frame through the second opening portion, thereby causing damage to the second electronic device.
According to recent enhancement in functions of slide type electronic devices, liquid crystal displays have been upsized and the number of operation buttons has been increased. As a result, the number of lines in wiring which connects a first electronic component and a second electronic component to each other has been increased, and the dimension such as the width has been increased. First opening portions and second opening portions have also been upsized so as to correspond to wiring having increased dimensions. Therefore, the probability that foreign substances enter a frame has been increased as well.